A detailed insight into anion sensing based on intramolecular charge transfer (ICT) mechanism: A comprehensive review of the years 2016 to 2021

Dental caries, otherwise known as tooth decay, is one of the most prevalent chronic diseases of people worldwide; individuals are susceptible to this disease throughout their lifetime. Dental caries forms through a complex interaction over time between acid-producing bacteria and fermentable carbohydrate, and many host factors including teeth and saliva. The disease develops in both the crowns and roots of teeth, and it can arise in early childhood as an aggressive tooth decay that affects the primary teeth of infants and toddlers. Risk for caries includes physical, biological, environmental, behavioural, and lifestyle-related factors such as high numbers of cariogenic bacteria, inadequate salivary flow, insufficient fluoride exposure, poor oral hygiene, inappropriate methods of feeding infants, and poverty. The approach to primary prevention should be based on common risk factors. Secondary prevention and treatment should focus on management of the caries process over time for individual patients, with a minimally invasive, tissue-preserving approach.

Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2(•-) is rather scarce. In addition, numerous studies on O2(•-) were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2(•-) reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2(•-) so as to enable researchers to venture into future research. It comprises the main characteristics of O2(•-) followed by generation methods. The reaction types of O2(•-) are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2(•-) environmental chemistry is also discussed. The detection methods of O2(•-) are categorized and elaborated. Special attention is given to the feasibility of using ionic liquids as media for O2(•-), addressing the latest progress of generation and applications. The effect of electrodes on the O2(•-) electrochemical generation is reviewed. Finally, some remarks and future perspectives are concluded.